1. Field of the Invention
The invention relates in general to a diode structure, and more particularly to a light emitting diode structure with multiple current blocking layers.
2. Description of the Related Art
Normally, the current direction of a light emitting diode is the shortest path through which most of the current flows to the area under electrodes. Consequentially, most of the light concentrates under the electrodes and becomes blocked, and the brightness is thus decreased.
Currently, a single-layer current blocking layer is used to block the current from flowing to the shortest path, so that the current of the light emitting diode flows towards other paths to improve the distribution of current. Then, a current spreading layer covers the current blocking layer so as to increase the brightness and improve the brightness of elements.
Conventionally, a thickness of the current blocking layer is increased to facilitate the spreading of the current. However, in subsequent process of covering the current blocking layer with a current spreading layer, the current spreading layer may become too thin and break easily at the part with step coverage. Besides, when the thickness of the current spreading layer reaches a certain level (such as above 600 Å), the current spreading layer may absorb the light and result in light emitting loss, therefore the current spreading layer with a smaller thickness is used. However, when the current spreading layer is too thin, the current spreading layer may easily break at the part with step coverage, impeding the spreading of the current and incapacitating the normal operation of the light emitting diode.